Yellow toner

ABSTRACT

To provide a yellow toner that it provides a sharper color than ever before in small amounts and the hue is greener than ever before, whereby the color range can be increased. Disclosed is a yellow toner containing a binder resin and a yellow colorant, wherein, as the yellow colorant, a compound A represented by the following general formula (1) and a compound B represented by the following formula (2) are contained, and wherein, with respect to 100 parts by mass of the binder resin, a content of the compound A is from 0.5 to 7.5 parts by mass, and a content of the compound B is from 0.5 to 8.0 parts by mass:

TECHNICAL FIELD

The present invention relates to a yellow toner that it provides asharper color than ever before in small amounts and the hue is greenerthan ever before, whereby the color range can be increased.

BACKGROUND ART

In an image forming device such as an electrophotographic device and anelectrostatic recording device, first, an electrostatic latent imageformed on the photoconductor is developed with a toner. Next, as needed,a toner image thus formed is transferred onto a transfer material suchas a paper sheet and then fixed thereon by various methods such asheating, pressurization or solvent fume.

In the field of such an image forming device, a digital full-colorcopying machine and a digital full-color printer have been put topractical use. A digital full-color copying machine produces afull-color image as follows. First, an original color image is subjectedto color separation with blue, green and red filters; an electrostaticlatent image corresponding to the original color image, which iscomposed of dots that are 20 to 70 μm in diameter, is developed withyellow, magenta, cyan and black toners; and a full-color image is formedusing the subtractive color mixing effect.

Recently, there is an increasing demand for full-color images with highimage quality and high resolution. Especially, to increase colorreproducibility, it is hoped that an image can be printed in the samehue as ink printing.

As a color pigment for a yellow toner, for example, a disazo pigment astypified by C.I. Pigment Yellow 12, 13 and 17, and a monoazo pigment astypified by C.I. Pigment Yellow 74, 97 and 98 have been generally used.

Besides the combinations of yellow pigments, examples of improving tonerproperties by combining a yellow pigment and a yellow dye, are known.

Patent Literature 1 discloses a yellow toner comprising C.I. PigmentYellow 74 and C.I. Solvent Yellow 162. In Patent Literature 1, it isdescribed that by containing these colorants, the toner obtainssatisfactory color tone that is obtained in the case of incorporatingC.I. Pigment Yellow 74 solely in a toner, and high coloring power ofC.I. Solvent Yellow 162.

Patent Literature 2 discloses a yellow toner comprising, as colorants,C.I. Pigment Yellow 155 and C.I. Solvent Yellow 162 at a specific ratio.Patent Literature 2 describes that due to the colorants contained at thespecific ratio and due to the excellent compatibility of C.I. SolventYellow 162 with binder resin, the dispersibility of C.I. Pigment Yellow155 can be further increased, and more stable charging property andbetter transparency can be obtained.

Patent Literature 3 discloses a yellow toner comprising C.I. SolventYellow 162, a condensed azo pigment (e.g., C.I. Pigment Yellow 93) andso on. Patent Literature 3 describes that the aggregation of thecondensed azo pigment (e.g., C.I. Pigment Yellow 93) can be suppressedby the use of C.I. Solvent Yellow 162, so that the dispersibility of thecondensed azo pigment can be increased, and more uniform triboelectricchargeability can be obtained.

CITATION LIST

Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No.2006-126383

Patent Literature 2: JP-A No. 2006-313302

Patent Literature 3: JP-A No. 2000-162824

SUMMARY OF INVENTION Technical Problem

The applications of an electrophotographic image forming device havebeen extended from general copying machines and printers used to printor copy office documents, to the field of production of printed mattersfor use outside the office, in particular, to the print-on-demand (POD)market that is an area of quick printing, since the image forming devicecan easily print variable information from electronic data. Therefore,in recent years, the level of demand required of the reflection densityand chroma of a printed product has been rapidly increased.

Unlike a pigment, a dye is characterized by solubility in solvents andpoor resistance to light. Accordingly, a combination of a dye and apigment has a problem in that there is a decrease in light resistancewhen the content ratio of the dye is too large. Therefore, a limitationis imposed on the content ratio of the dye and the pigment.

From the viewpoint of downsized image forming devices and less energyconsumption, there is a demand for reduction in toner consumption inprinting. However, printing with a small amount of toner has a problemin that there is a decrease in chroma and color range. Also, the tonersusing the dyes described in Patent Literatures 1 to 3 cannot obtain asufficiently wide color range when the toner amount is small.

An object of the present invention is to provide a yellow toner that itprovides a sharper color than ever before in small amounts and the hueis greener than ever before, whereby the color range can be increased.

Solution to Problem

To attain the object, the inventor of the present invention conducteddetailed research and found the following: by using the combination ofcompounds A and B as a yellow colorant, each of which has a specificchemical structure, such a yellow toner is obtained, that it provides asharper color than ever before in small amounts and the hue is greenerthan ever before, whereby the color range can be increased. Based onthis finding, the inventor achieved the present invention.

The yellow toner of the present invention is a yellow toner comprising abinder resin and a yellow colorant, wherein, as the yellow colorant, acompound A represented by the following general formula (1) and acompound B represented by the following formula (2) are contained, andwherein, with respect to 100 parts by mass of the binder resin, acontent of the compound A is from 0.5 to 7.5 parts by mass, and acontent of the compound B is from 0.5 to 8.0 parts by mass:

where R^(1A), R^(1B), R^(2A) and R^(2B) are each independently a halogenatom, an alkyl group, a methoxy group, an amino group, a nitro group, anacetylamido group (—MHCOCH₃), a methyl ester group (—COOCH₃) or aprimary amide group (—CONH₂);

-   R³ is a halogen atom;-   R⁴ and R⁵ are each independently a halogen atom, an alkyl group, a    methoxy group, an amino group, a nitro group, an acetylamido group    (—NHCOCH₃), an acetyl group (—COCH₃), a methyl ester group (—COOCH₃)    or a primary amide group (—CONH₂);-   a1 and b1 are positive integers that a sum of the positive integers    is 1 or more and 3 or less;-   a2 and b2 are positive integers that a sum of the positive integers    is 1 or more and 3 or less;-   c is an integer of 1 or more and 3 or less; and d and e are each    independently 1 or 2,

In the present invention, a mass ratio of the content of the compound Ato the content of the compound B (compound A/compound B) is preferablyfrom 0.1 to 10.0.

Advantageous Effects of Invention

According to the present invention as described above, by using thecompound A having the chemical structure represented by the generalformula (1) in combination with the compound B, due to the presence ofthe compound A, the dispersion stability of the compound B in thepolymerizable monomer composition or binder resin is increased;therefore, such a yellow toner is provided, that it provides a sharpercolor than ever before in small amounts and the hue is greener than everbefore, whereby the color range can be increased.

DESCRIPTION OF EMBODIMENTS

The yellow toner of the present invention is a yellow toner comprising abinder resin and a yellow colorant, wherein, as the yellow colorant, acompound A represented by the following general formula (1) and acompound B represented by the following formula (2) are contained, andwherein, with respect to 100 parts by mass of the binder resin, acontent of the compound A is from 0.5 to 7.5 parts by mass, and acontent of the compound B is from 0.5 to 8.0 parts by mass:

where R^(1A), R^(1B), R^(2A) and R^(2B) are each independently a halogenatom, an alkyl group, a methoxy group, an amino group, a nitro group, anacetylamido group (—NHCOCH₃), a methyl ester group (—COOCH₃) or aprimary amide group (—CONH₂); R³ is a halogen atom; R⁴ and R⁵ are eachindependently a halogen atom, an alkyl group, a methoxy group, an aminogroup, a nitro group, an acetylamido group (—NHCOCH₃), an acetyl group(—COCH₃), a methyl ester group (—COOCH₃) or a primary amide group(—CONH₂); a1 and b1 are positive integers that a sum of the positiveintegers is 1 or more and 3 or less; a2 and b2 are positive integersthat a sum of the positive integers is 1 or more and 3 or less; c is aninteger of 1 or more and 3 or less; and d and e are each independently 1or 2,

Hereinafter, the yellow toner or the present invention may be simplyreferred to as “toner”.

Hereinafter, a method for producing yellow colored resin particles usedin the present invention (hereinafter they may be simply referred to as“colored resin particles”), yellow colored resin particles obtained bythe production method, a method for producing a yellow toner using theyellow colored resin particles, and the yellow toner of the presentinvention will be described in order.

1. Method for Producing Colored Resin Particles

Generally, methods for producing colored resin particles are broadlyclassified into dry methods such as a pulverization method and wetmethods such as an emulsion polymerization agglomeration method, asuspension polymerization method and a solution suspension method. Thewet methods are preferred since a toner that has excellent printingcharacteristics such as image reproducibility can be easily obtained.Among the wet methods, polymerization methods such as the emulsionpolymerization agglomeration method and the suspension polymerizationmethod are preferred, since a toner that has relatively small particlesize distribution in micron order-can be easily obtained. Among thepolymerization methods, the suspension polymerization method is morepreferred.

The emulsion polymerization agglomeration method is a method forproducing colored resin particles by polymerizing emulsifiedpolymerizable monomers to obtain a resin microparticle emulsion, andaggregating the resulting resin microparticles with a colorantdispersion, etc. The solution suspension method is a method forproducing colored resin particles by forming droplets of a solution inan aqueous medium, the solution containing toner-components such as abinder resin and a colorant dissolved or dispersed in an organicsolvent, and removing the organic solvent. Both methods can be carriedout by known methods.

The colored resin particles used in the present invention can beproduced by the wet methods or the dry methods. The wet methods arepreferred, and among the wet methods, the suspension polymerizationmethod is particularly preferred. By the suspension polymerizationmethod, the colored resin particles are produced through the processesdescribed below.

(A) Suspension Polymerization Method

(A-1) Preparation Process of Polymerizable Monomer Composition

First, a polymerizable monomer, a yellow colorant, and other additivesadded as needed, such as a charge control agent and a release agent, aremixed to prepare a polymerizable monomer composition. For example, amedia type dispersing machine is used for the mixing in the preparationof the polymerizable monomer composition.

In the present invention, the polymerizable monomer means a monomerhaving a polymerizable functional group, and the polymerizable monomeris polymerized into a binder resin. As a main component of thepolymerizable monomer, a monovinyl monomer is preferably used. As themono-vinyl monomer, examples include, but are not limited to, styrene;styrene derivatives such as vinyl toluene and α-methylstyrene; acrylicacid and methacrylic acid; acrylic acid esters such as methyl acrylate,ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylateand dimethylaminoethyl acrylate; methacrylic acid esters such as methylme thacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, 2-ethylhexyl methacrylate and dimethylaminoethylmethacrylate; nitrile compounds such as acrylonitrile andmethacrylonitrile; amide compounds such as acrylamide andmethacrylamide; and olefins such as ethylene, propylene and butylene.These monovinyl monomers may be used alone or in combination of two ormore kinds. Among them, styrene, styrene derivatives, and derivatives ofacrylic acids or methacrylic acids are preferably used as the monovinylmonomer.

In order to improve hot offset and storage stability, it is preferableto use a crosslinkable polymerizable monomer together with the monovinylmonomer. The crosslinkable polymerizable monomer means a monomer havingtwo or more polymerizable functional groups. As the crosslinkablepolymerizable monomer, examples include, but are not limited to,aromatic divinyl compounds such as divinyl benzene, divinyl naphthaleneand derivatives thereof; ester compounds such as ethylene glycoldimethacrylate and diethylene glycol dimethacrylate, in which two ormore carboxylic acids are esterified to alcohol having two or morehydroxyl groups; other divinyl compounds such as N,N-divinylaniline anddivinyl ether; and compounds having three or more vinyl groups. Thesecrosslinkable polymerizable monomers can be used alone or in combinationof two or more kinds.

In the present invention, it is desirable that the amount of thecrosslinkable polymerizable monomer is generally from 0.1 to 5 parts bymass, and preferably from 0.3 to 2 parts by mass, with respect to 100parts by mass of the monovinyl monomer.

Also, it is preferable to use a macromonomer as a part of thepolymerizable monomer, since the balance between the storage stabilityand low-temperature fixability of the toner to be obtained can beimproved. The macromonomer is a reactive oligomer or polymer having apolymerizable carbon-carbon unsaturated double bond at the end of apolymer chain and generally having a number average molecular mass offrom 1,000 to 30,000. The macromonomer is preferably one that canprovide a polymer having a higher glass transition temperature(hereinafter may be referred to as “Tg”) than a polymer obtained bypolymerization of a monovinyl monomer. The amount of the macromonomer ispreferably from 0.03 to 5 parts by mass, and more preferably from 0.05to 1 part by mass, with respect to 100 parts by mass of the monovinylmonomer.

In the present invention, the compound A and the compound B arecontained as the yellow colorant.

Hereinafter, the compound A used in the present invention will bedescribed in detail.

The compound A of the present invention is a disazo compound representedby the following general formula (1):

In the general formula (1), R^(1A), R^(1B), R^(2A) and R^(2B) are eachindependently a halogen atom, an alkyl group, a methoxy group, an aminogroup, a nitro group, an acetylamido group (—NHCOCH₃), a methyl estergroup (—COOCH₃) or a primary amide group (—CON₂). It is preferable thatR^(1A), R^(1B), R^(2A) and R^(2B) are each independently a methyl group,a methoxy group, an amino group, a nitro group, an acetylamido group ora primary amide group. It is more preferable that R^(1A) and R^(2A) aremethyl groups, and R^(1B) and R^(2B) are primary amide groups. Each ofR^(1A), R^(1B), R^(2A) and R^(2B) may have a bond with any carbon atomon the benzene ring (except the carbon atom bound to the azo group(—N═N—)).

In the general formula (1), a1 and b1 are positive integers that a sumof the positive integers is 1 or more and 3 or less, and a2 and b2 arepositive integers that a sum of the positive integers is 1 or more and 3or less. It is preferable that a1, b1, a2 and b2 are each 1.

In the general formula (1), R³ is a halogen atom and is preferably achlorine atom. R³ may have a bond with any carbon atom on the benzenering (except the carbon atoms bound to the amide groups (—CO—NH-)).

In the general formula (1), c is an integer of 1 or more and 3 or less,and it is preferably 1.

In the general formula (1), R⁴ and R⁵ are each independently a halogenatom, an alkyl group, a methoxy group, an amino group, a nitro group, anacetylamido group (—NHCOCH₃), an acetyl group (—COCH₃), a methyl estergroup (—COOCH₃) or a primary amide group (—CONH₂). It is preferable thatR⁴ and R³ are acetyl groups.

In the general formula (1), d and e are each independently 1 or 2. It ispreferable that d and e are 1.

As the compound A represented by the general formula (1), examplesinclude, but are not limited to, the following compounds. Of thefollowing examples, the compound represented by the following formula(1A) is C.I. Pigment Yellow 214 (CAS Ho. 254430-12-5) and the compoundrepresented by the following formula (1B) is C.I. Pigment Yellow 219(CAS No. 347174-87-2).

The compound A used in the present invention is not limited to thefollowing examples. Tautomers of the following examples can be alsopreferably used as the compound A of the present invention.

The compound A may be a commercially-available product or may besynthesized in advance.

As the method for synthesizing the compound A, examples include, but arenot limited to, a method of coupling one equivalent of anN,N′-1,4-diacetylphenylenediamine derivative represented by thefollowing general formula (a) with two equivalents of a benzenediazoniumderivative represented by the following general formula (b) (seeJapanese Examined Patent Application Publication No. 48-13692).

where R³, R⁴ and R⁵ are the same groups as R³, R⁴ and R⁵ in the generalformula (1), respectively, and c, d and e are the same numbers as c, dand e in the general formula (1), respectively.

where R^(1A′) is the same group as R^(1A) or R^(2A) in the generalformula (1); R^(1B′) is the same group as R^(1B) or R^(2B) in thegeneral formula (1); a1′ is the same number as a1 or a2 in the generalformula (1); and b1′ is the same number as b1 or b2 in the generalformula (1).

The content of the compound A is from 0.5 to 7.5 parts by mass,preferably from 1.0 to 7.0 parts by mass, more preferably from 2.0 to6.5 parts by mass, and still more preferably from 3.0 to 6.0 parts bymass, with respect to 100 parts by mass of the binder resin. When thecontent of the compound A is less than 0.5 part by mass with respect to100 parts by mass of the binder resin, the hue angle is lowered andmakes the yellow toner less green. When the content of the compound A ismore than 7.5 parts by mass with respect to 100 parts by mass of thebinder resin, the particle size distribution of the toner thus obtaineddeteriorates.

In the present invention, besides the compound A, the compound Brepresented by the following formula (2) (C.I. Solvent Yellow 162, CASNo. 104244-10-2) is contained as the yellow colorant.

The content of the compound B is from 0.5 to 8.0 parts by mass,preferably from 3.0 to 7.0 parts by mass, and more preferably from 4.0to 6.0 parts by mass, with respect to 100 parts by mass of the binderresin. When the content of the compound B is less than 0.5 part by masswith respect to 100 parts by mass of the binder resin, a target chromais not obtained. When the content of the compound B is more than 8.0parts by mass with respect to 100 parts by mass of the binder resin,poor light resistance is obtained. This is because a dye like thecompound B is liable to UV-induced color deterioration.

In the present invention, the mass ratio of the content of the compoundA to the content of the compound B (compound A/compound B) is preferablyfrom 0.1 to 10.0.

When the mass ratio is less than 0.1 or when the mass ratio is more than10.0, the yellow toner may be less green or low in chroma. Since themass ratio (compound A/compound B) is from 0.1 to 10.0, both thereflection density and chroma of the yellow toner can be increased withbalance.

The principle of the effect provided by the use of the combination ofthe compounds A and B, is not clear. However, it is considered asfollows: by using the combination of the compounds, due to the presenceof the compound A having the specific chemical structure, the dispersionstability of the compound B in the polymerizable monomer composition orbinder resin is increased; therefore, the yellow toner thus obtained issuch a toner that it provides a sharper color than ever before and thehue is greener than ever before, whereby the color range is increased.

As another additive, a positively or negatively chargeable chargecontrol agent can be used to improve the chargeability of the toner.

The charge control agent is not particularly limited, as long as it isone that is generally used as a charge control agent for toners. Amongcharge control agents, a positively or negatively chargeable chargecontrol resin is preferred, since the charge control resin is highlycompatible with the polymerizable monomer and can impart stablechargeability (charge stability) to the toner particles. From theviewpoint of obtaining a positively chargeable toner, a positivelychargeable charge control resin is more preferred.

As the positively chargeable charge control agent, examples include, butare not limited to, a nigrosine dye, a quaternary ammonium salt, atriaminotriphenylmethane compound, an imidazole compound, a polyaxaineresin, a quaternary ammonium group-containing copolymer, and aquaternary ammonium salt group-containing copolymer, which arepreferably used as the charge control resin.

As the negatively chargeable charge control agent, examples include, butare not limited to, an azo dye containing a metal such as Cr, Co, Al andFe; a metal salicylate compound; a metal alkylsalicylate compound; and asulfonic acid group-containing copolymer, a sulfonic acid saltgroup-containing copolymer, a carboxylic acid group-containing copolymerand a carboxylic acid salt group-containing copolymer, which arepreferably used as the charge control resin.

In the present invention, it is desirable that the amount of the chargecontrol agent is generally from 0.01 to 10 parts by mass, and preferablyfrom 0.03 to 8 parts by mass, with respect to 100 parts by mass of themonovinyl monomer. When the added amount of the charge control agent isless than 0.01 part by mass, fog may occur. On the other hand, when theadded amount of the charge control agent is more than 10 parts by mass,soiling in printing may occur.

As another additive, a molecular weight modifier is preferably used inthe polymerization of the polymerizable monomer that is polymerized intoa binder resin.

The molecular weight modifier is not particularly limited, as long as itis one that is generally used as a molecular weight modifier for toners.As the molecular weight modifier, examples include, but are not limitedto, mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octylmercaptan and 2,2,4,6,6-pentamethylheptane-4-thiol, and thiuramdisulfides such as tetramethyl thiuram disulfide, tetraethyl thiuramdisulfide, tetrabutyl thiuram disulfide, N,N′-dimethyl-N,N′-diphenylthiuram disulfide, and N,N′-dioctadecyl-N,N′-diisopropyl thiuramdisulfide. These molecular weight modifiers may be used alone or incombination of two or more kinds.

In the present invention, it is desirable that the amount of themolecular weight modifier is generally from 0.01 to 10 parts by mass,and preferably 0.1 to 5 parts by mass, with respect to 100 parts by massof the monovinyl monomer.

As another additive, it is preferable to add a release agent. By addingthe release agent, the releasability of the toner from a fixing rollerupon fixing, can be improved. The release agent is not particularlylimited, as long as it is one that is generally used as a release agentin toner. As the release agent, examples include, but are not limitedto, low-molecular-weight polyolefin waxes and modified waxes thereof;natural plant waxes such as jojoba; petroleum waxes such as paraffin;mineral waxes such as ozokerite; synthetic waxes such as Fischer-Tropschwax; and polyalcohol esters such as dipentaerythrito1 ester. Of them,polyalcohol esters are preferred since the toner can achieve a balancebetween storage stability and low-temperature fixability. These releaseagents may be used alone or in combination of two or more kinds.

The amount of the release agent is preferably from 0.1 to 30 parts bymass, and more preferably from 1 to 20 parts by mass, with respect to100 parts by mass of the monovinyl monomer.

(A-2) Suspension Process of Obtaining Suspension (Droplets FormingProcess)

In the present invention, the polymerizable monomer compositioncontaining the polymerizable monomer and the yellow colorant isdispersed in an aqueous medium containing a dispersion stabilizer, and apolymerization initiator is added therein. Then, the polymerizablemonomer composition are formed into droplets. The method for forming thedroplets is not particularly limited. For example, the droplets areformed by means of a device capable of strong stirring, such as an(in-line type) emulsifying and dispersing machine (product name: Milder,manufactured by: Pacific Machinery & Engineering Co., Ltd.) and ahigh-speed emulsifying and dispersing machine (product name: T. K.Homomixer Mark II, manufactured by: PRIMIX Corporation).

As the polymerization initiator, examples include, but are not limitedto, persulfates such as potassium, persulfate and ammonium persulfate;azo compounds such as 4,4′-azobis(4-cyanovaleric acid),2,2′-azobis(2-methyl-H-(2-hydroxyethyl)propionamide),2,2′-azobis(2-amidinopropane)dihydrochloride,2,2′-azobis(2,4-dimethylvaleronitrile) and 2,2′-azobisisobutyronitrile;and organic peroxides such as di-t-butylperoxide, benzoylperoxide,t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylbutanoate,diisopropylperoxydicarbonate, di-t-butylperoxyoxyisophthalate andt-butylperoxyisobutyrate. They can be used alone or in combination oftwo or more kinds. Among them, organic peroxides are preferred sincethey can reduce residual polymerizable monomer and impart excellentprinting durability.

Among organic peroxides, preferred are peroxy esters, and more preferredare non-aromatic peroxy esters, i.e., peroxy esters having no aromaticring, since they have excellent initiator efficiency and can reduceresidual polymerizable monomer.

The polymerization initiator may be added after the polymerizablemonomer composition is dispersed into the aqueous medium and before thepolymerizable monomer composition is formed into droplets as describedabove, or it may be added to the polymerizable monomer compositionbefore the polymerizable monomer composition is dispersed into theaqueous medium.

The added amount of the polymerization initiator used for thepolymerization of the polymerizable monomer composition, is preferablyfrom 0.1 to 20 parts by mass, more preferably from 0.3 to 15 parts bymass, and even more preferably from 1 to 10 parts by mass, with respectto 100 parts by mass of the monovinyl monomer.

In the present invention, the aqueous medium means a medium containingwater as a main component.

In the present invention, the dispersion stabilizer is preferably addedto the aqueous medium. As the dispersion stabilizer, examples include,but are not limited to, inorganic compounds including sulfates such asbarium sulfate and calcium sulfate, carbonates such as barium carbonate,calcium carbonate and magnesium carbonate, phosphates such as calciumphosphate, metal oxides such as aluminum oxide and titanium, oxide, andmetal hydroxides such as aluminum hydroxide, magnesium hydroxide andiron (II) hydroxide, and organic compounds including water-solublepolymers such as polyvinyl alcohol, methyl cellulose and gelatin,anionic surfactants, nonionic surfactants, and ampholytic surfactants.These dispersion stabilizers can be used alone or in combination of twoor more kinds.

Among the above dispersion stabilizers, preferred are colloids ofinorganic compounds, and particularly preferred is a colloid of a hardlywater-soluble metal hydroxide. By using a colloid of an inorganiccompound, particularly a colloid of a hardly water-soluble metalhydroxide, the colored resin particles can have a narrow particle sizedistribution, and the amount of the dispersion stabilizer remainingafter washing can be small, so that the polymerization toner thusobtained can clearly reproduce an image and does not deteriorateenvironmental stability.

(A-3) Polymerization Process

Formation of the droplets is carried out as described under the above(A-2). The thus-obtained aqueous dispersion medium is heated topolymerize, thereby forming an aqueous dispersion containing the yellowcolorant.

The polymerization temperature of the polymerizable monomer compositionis preferably 50° C. or more, and more preferably from 60 to 95° C. Thepolymerization reaction time is preferably from 1 to 20 hours, and morepreferably from 2 to 15 hours.

The colored resin particles may be used as they are as a polymerizationtoner, or they may be mixed with an external additive and used as apolymerization toner. It is preferable that the colored resin particlesare so-called core-shell type (or “capsule type”) colored resinparticles obtained by using the colored resin particles as a core layerand forming a shell layer, which is a layer that is different from thecore layer, around the core layer. By covering the core layer composedof a substance having a low softening point with a substance having ahigher softening point, the core-shell type colored resin particles canachieve a balance between lowering of fixing temperature and preventionof aggregation during storage.

A method for producing the above-mentioned core-shell type colored resinparticles using the colored resin particles, is not particularlylimited. The core-shell type colored resin particles can foe produced bya conventional method. The in situ polymerization method and the phaseseparation method are preferable from the viewpoint of productionefficiency.

Hereinafter, the method for producing the core-shell type colored resinparticles by the in situ polymerization method, will be described.

The core-shell type colored resin particles can be obtained by adding apolymerizable monomer for forming a shell layer (a polymerizable monomerfor shell) and a polymerization initiator to an aqueous medium in whichthe colored resin particles are dispersed, and then polymerizing themixture.

As the polymerizable monomer for shell, the above-mentioned.polymerizable monomers can be used. Among the polymerizable monomers, itis preferable to use monomers that can provide a polymer having a Tg ofmore than 80° C., such as styrene, acrylonitrile and methylmethacrylate, alone or in combination of two or more kinds.

As the polymerization initiator used for polymerization of thepolymerizable monomer for shell, examples include, but are not limitedto, water-soluble polymerization initiators including metal persulfatessuch as potassium persulfate and ammonium persulfate, and azo-typeinitiators such as 2,2′-azobis(2-methyl-N-(2-hydroxyethyl)propionamide)and2,2′-azobis(2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide).These polymerization initiators can be used alone or in combination oftwo or more kinds. The amount of the polymerization initiator ispreferably from 0.1 to 30 parts by mass, and more preferably from 1 to20 parts by mass, with respect to 100 parts by mass of the polymerizablemonomer for shell.

The polymerization temperature of the shell layer is preferably 50° C.or more, and more preferably from 60 to 95° C. The polymerizationreaction time is preferably from 1 to 20 hours, and more preferably from2 to 15 hours.

(A-4) Washing, Filtering, Dehydrating and Drying Processes

After the polymerization is completed, the aqueous dispersion of thecolored resin particles obtained by the polymerization is preferablysubjected to operations of filtering, washing for removal of thedispersion stabilizer, dehydrating and drying, several times as needed,according to a conventional method.

The washing is preferably carried out by the following method. When theinorganic compound is used as the dispersion stabilizer, acid or alkaliis added to the aqueous dispersion of the colored resin particles,thereby dissolving the dispersion stabilizer in water and removing it.When the colloid of the hardly water-soluble inorganic hydroxide is usedas the dispersion stabilizer, the pH of the aqueous dispersion of thecolored resin particles is controlled to 6.5 or less by adding acid. Asthe acid, examples include, but are not limited to, inorganic acids suchas sulfuric acid, hydrochloric acid and nitric acid, and organic acidssuch as formic acid and acetic acid. Sulfuric acid is particularlypreferred for its high removal efficiency and small impact on productionfacilities.

The dehydrating and filtering method is not particularly limited and canbe selected from various known methods. As the method, examples include,but are not limited to, a centrifugal filtration method, a vacuumfiltration method and a pressure filtration method. Also, the dryingmethod is not particularly limited and can be selected from variousmethods.

(B) Pulverization Method

In the case of producing the colored resin particles by employing thepulverization method, the colored resin particles are produced by thefollowing processes.

First, a binder resin, a yellow colorant, and other-additives added asneeded, such as a charge control agent and a release agent, are mixed bymeans of a mixer such as a bail mill, a V-type mixer, FM Mixer (productname), a high-speed dissolver, an internal mixer or Forberg.

Next, while heating the thus-obtained mixture, the mixture is kneaded bymeans of a press kneader, a twin screw kneading machine, a roller or thelike. The thus-obtained kneaded product is coarsely pulverized by meansof a pulverizer such as a hammer mill, a cutter mill or a roller mill,finely pulverized by means of a pulverizer such as a jet mill or ahigh-speed rotary pulverizer, and then classified into a desiredparticle diameter by means of a classifier such as a wind classifier oran airflow classifier, thereby obtaining the colored resin particlesproduced by the pulverization method.

In the pulverization method, those that are provided above under “(A)Suspension polymerization method” can be used as the binder resin, theyellow colorant, and the other additives added as needed, such as thecharge control agent and the release agent. Similarly to the coloredresin particles obtained by the above “(A) Suspension polymerizationmethod”, the colored resin particles obtained by the pulverizationmethod can be core-shell type colored resin particles by a method suchas the in situ polymerization method.

As the binder resin, resins that have been widely used for toners can beused. As the binder resin used in the pulverization method, examplesinclude, but are not limited to, polystyrene, styrene-butyl acrylatecopolymers, polyester resins and epoxy resins.

2. Colored Resin Particles

The colored resin particles containing the yellow colorant are obtainedby the production method such as the above-mentioned “(A) Suspensionpolymerization method” or “(B) Pulverization method”.

Hereinafter, the colored resin particles constituting the toner will bedescribed. The colored resin particles described below encompass bothcore-shell type colored resin particles and colored resin particles ofother types.

The volume average particle diameter (Dv) of the colored resin particlesis preferably from 3 to 15 μm, and more preferably from 4 to 12 μm. Whenthe volume average particle diameter (Dv) is less than 3 μm, theflowability of the polymerization toner decreases and may deterioratetransferability or decrease image density. When the volume averageparticle diameter (Dv) is more than 15 μm, image resolution maydecrease.

For the colored resin particles, the ratio (Dv/Dn) of the volume averageparticle diameter (Dv) and the number average particle diameter (Dn) ispreferably from 1.0 to 1.3, and more preferably from 1.0 to 1.2. Whenthe ratio Dv/Dn is more than 1.3, there may be a decrease intransferability, image density and resolution. The volume averageparticle diameter and number average particle diameter of the coloredresin particles can be measured by means of a particle size analyzer(product name: Multisizer, manufactured by: Beckman Coulter, Inc.), forexample.

The average circularity of the colored resin particles of the presentinvention is preferably from 0.96 to 1.00, more preferably from 0.97 to1.00, and even more preferably from 0.98 to 1.00, from the viewpoint ofimage reproducibility.

When the average circularity of the colored resin particles is less than0.96, thin line reproducibility in printing may deteriorate.

As the toner of the present invention, the colored resin particlescontaining the yellow colorant can be used as they are. From theviewpoint of controlling the chargeability, flowability and storagestability of the toner, the colored resin particles may be used as aone-component toner by mixing and stirring the colored resin particleswith the external additives to attach the external additives to thesurface of the colored resin particles.

The one-component toner may be mixed and stirred with carrier particlesto obtain a two-component developer.

A stirrer is used to cover the colored resin particles with the externaladditives. The stirrer is not particularly limited, as long as it is astirring device that can attach the external additives to the surface ofthe colored resin particles. For example, the colored resin particlescan be covered with the external additives by means of a stirrer that iscapable of mixing and stirring, such as FM Mixer (product name,manufactured by: Nippon Coke & Engineering Co., Ltd.), Super Mixer(product name, manufactured by: Kawata Manufacturing Co., Ltd.), Q Mixer(product name, manufactured by: Nippon Coke & Engineering Co., Ltd.),Mechanofusion System (product name, manufactured by: Hosokawa MicronCorporation) and Mechanomill (product name, manufactured by: Okada SeikoCo., Ltd.)

As the external additives, examples include, but are not limited to,inorganic fine particles composed of silica, titanium oxide, aluminumoxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphateand/or cerium, oxide, and organic fine particles composed of polymethylmethacrylate resin, silicone resin and/or melamine resin. Of them,inorganic fine particles are preferred. Of inorganic fine particles,silica and/or titanium oxide is preferred, and fine particles composedof silica, are particularly preferred.

These external additives can be used alone. However, it is preferable touse them in combination of two or more kinds.

In the present invention, it is desirable that the external additivesare used in an amount of generally from 0.05 to 6 parts by mass,preferably from 0.2 to 5 parts by mass, with respect to 100 parts bymass of the colored resin particles. When the added amount of theexternal additives is less than 0.05 part by mass, toner transferabilitymay decrease. When the added amount of the external additives is morethan 6 parts by mass, fog may occur.

4. Toner of the Present Invention

The toner of the present invention obtained through the above steps usesthe combination of the compound A and the compound B as the yellowcolorant: therefore, the toner of the present invention is a yellowtoner that it provides a sharper color than ever before in small amountsand the hue is greener than ever before, whereby the color range can beincreased.

EXAMPLES

Hereinafter, the present invention will be described further in detail,with reference to examples and comparative examples. However, the scopeof the present invention may not be limited to the following examples.Herein, “part(s)” and are based on mass if not particularly mentioned.

1. Production of Colored Resin Particles <Colored Resin Particles (1)>1-1. Preparation of Polymerizable Monomer Composition for Core

The following raw materials were subjected to wet pulverization by meansof a media-type disperser (product name: PICO MILL, manufactured by:Asada Iron Works Co., Ltd.): 75 parts of styrene, 25 parts of n-butylacrylate, 0.1 part of a polymethacrylic acid ester macromonomer (productname: AA6, manufactured by: TOAGOSEI Co., Ltd., Tg: 94° C.), 0.7 part ofdivinylbenzene, 1.0 part of tetraethylthiuram disulfide and, as yellowcolorant, 4.5 parts of C.I. Pigment Yellow 214 (represented by thefollowing formula (1A), product name: PV Fast Yellow H9G VP2430,manufactured by: Clariant Corp., CAS No. 254430-12-5) and 3.0 parts ofC.I. Solvent Yellow 162 (product name: Neptun Yellow 075, manufacturedby: BASF). To a mixture obtained by the wet pulverization, 1.2 parts ofa charge control resin (product name: Acrybase FCA-161P, manufacturedby: Fujikura Kasei Co., Ltd.) and 10 parts of an ester wax (productname: WEP7, manufactured by: NOF Corporation) were added, mixed anddissolved to obtain a polymerizable monomer composition.

1-2. Preparation of Aqueous Dispersion Medium

An aqueous solution of 7.3 parts of sodium hydroxide dissolved in 50parts of ion-exchanged water, was gradually added to an aqueous solutionof 10.4 parts of magnesium, chloride dissolved in 280 parts ofion-exchanged water, while stirring, thereby preparing a magnesiumhydroxide colloid dispersion.

1-3. Preparation of Polymerizable Monomer for Shell

Meanwhile, 2 parts of methyl methacrylate and 130 parts of water weresubjected to a fine dispersion treatment by means of an ultrasonicemulsifying machine, thereby preparing an aqueous dispersion of apolymerizable monomer for shell.

1-4. Droplets Forming Process

The polymerizable monomer composition was put in the magnesium hydroxidecolloid dispersion (the magnesium hydroxide colloid amount: 5.3 parts)and stirred. Then, as a polymerization initiator, 6 parts oft-butylperoxy-2-ethylhexanoate was added thereto. The dispersioncontaining the polymerization initiator was subjected to dispersion at15,000 rpm using an in-line type emulsifying and dispersing machine(product name: Milder, manufactured by: Pacific Machinery & EngineeringCo., Ltd.), thereby forming the polymerizable monomer composition intodroplets.

1-5. Suspension Polymerization Process

The dispersion containing the droplets of the polymerizable monomercomposition was put in a reactor. The temperature thereof was increasedto 90° C. to start a polymerization reaction. After the polymerizationconversion rate reached almost 100%, a solution obtained by dissolving0.1 part of 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide] (awater-soluble polymerization initiator, product name: VA-086,manufactured by: Wako Pure Chemical Industries, Ltd.) in the aqueousdispersion for the polymerizable monomer for shell, was added in thereactor. Next, the temperature of the reactor was kept at 95° C for 4hours to continue the polymerization further. Then, the reactor wascooled by water to stop the reaction, thereby obtaining an aqueousdispersion of core-shell type colored resin particles.

1-6. Post-Treatment Process

The aqueous dispersion of the colored resin particles was subjected toacid washing (25° C., 10 minutes) in which, while stirring the aqueousdispersion, sulfuric acid was added thereto until the pH of the aqueousdispersion was 4.5 or less. Then, the colored resin particles wereseparated from the aqueous dispersion by filtration and washed withwater. The washing water was filtered. A filtrate thus obtained had anelectrical conductivity of 20 μS/cm. The colored resin particlessubjected to the washing and filtering processes were dehydrated anddried to obtain dried colored resin particles (1).

<Colored Resin Particles (2)>

Colored resin particles (2) were obtained in the same manner as theproduction method of the colored resin particles (1), except that in the“Preparation of polymerizable monomer composition for core”, the addedamount of C.I. Solvent Yellow 162 was changed from 3.0 parts to 4.5parts.

<Colored Resin Particles (3)>

Colored resin particles (3) were obtained in the same manner as theproduction method of the colored resin particles (1), except that in the“Preparation of polymerizable monomer composition for core”, the addedamount of C.I. Pigment Yellow 214 was changed from 4.5 parts to 2.0parts, and the added amount of C.I. Solvent Yellow 162 was changed from3.0 parts to 5.0 parts.

<Colored Resin Particles (4)>

Colored resin particles (4) were obtained in the same manner as theproduction method of the colored resin particles (1), except that in the“Preparation of polymerizable monomer composition for core”, 4.5 partsof C.I. Pigment Yellow 214 was changed to 4.5 parts of C. I. PigmentYellow 93 (represented by the following formula (X), product name:Cromophtal Yellow 3G, manufactured by: BASF, CAS No. 5580-57-4).

<Colored Resin Particles (5)>

Colored resin particles (5) were obtained in the same manner as theproduction method of the colored resin particles (1), except that in the“Preparation of polymerizable monomer composition for core”, 4.5 partsof C.I. Pigment Yellow 214 was changed to 4.5 parts of C.I. PigmentYellow 155 (represented by the following formula (Y), product name:Toner Yellow 3GP, manufactured by: Clariant Corp., CAS No. 68516-73-4.

<Colored Resin Particles (6)>

Colored resin particles (6) were obtained in the same manner as theproduction method of the colored resin particles (1), except that in the“Preparation of polymerizable monomer composition for core”, the addedamount, of C.I. Pigment Yellow 214 was changed from 4.5 parts to 8.0parts, and 3.0 parts of C.I. Solvent Yellow 162 was not used.

2. Evaluation of Properties of Colored Resin Particles

Measurement of volume average particle diameter (Dv) and calculation ofparticle size distribution (Dv/Dn) were carried out on the colored resinparticles (1) to (6).

About 0.1 g of a measurement sample (colored resin particles) wasweighed out and put in a beaker. As a dispersant, 0.1 mL of analkylbenzene sulfonic acid aqueous solution (product name: Driwel,manufactured by: Fujifilm Corporation) was added thereto. In addition,10 to 30 mL of Isoton II was added to the beaker. The mixture wasdispersed for three minutes with a 20W ultrasonic disperser. Then, thevolume average particle diameter (Dv) and number average particlediameter (Dn) of the colored resin particles were measured with aparticle diameter measuring device (product name: Multisizer,manufactured by: Beckman Coulter, Inc.) in the following conditions:

Aperture diameter: 100 μm

Medium: Isoton II

Number of measured particles: 100,000

Next, the particle size distribution (Dv/Dn) of the colored resinparticles was calculated.

3. Production of Yellow Toner

The colored resin particles (1) to (6) were covered with externaladditives to produce yellow toners of Examples 1 to 3 and ComparativeExamples 1 to 3.

Example 1

First, 0.6 part of hydrophobized silica fine particles having an averageparticle diameter of 7 nm and 1 part of hydrophobized silica fineparticles having an average particle diameter of 35 nm, were added to100 parts of the colored resin particles (1). They were mixed by meansof a high-speed stirrer (product name: FM Mixer, manufactured by: NipponCoke & Engineering Co., Ltd.) to prepare the yellow toner of Example 1.

Examples 2 and 3 and Comparative Examples 1 to 3

The yellow toners of Examples 2 and 3 and Comparative Examples 1 to 3were obtained in the same manner as Example 1, except that the coloredresin particles (1) were changed to, as shown in the following Table 1,any of the colored resin particles (2) to (6).

4. Evaluation of Toners for Developing Electrostatic Images

The image density, luminance (L*), color coordinate (a*, b*) and chroma(C*) of the yellow toners of Examples 1 to 3 and Comparative Examples 1to 3, were measured.

A commercially-available, non-magnetic one-component development colorprinter (printing rate: 20 sheets/min) was used. The toner cartridge ofthe development device was filled with a sample yellow toner, andprinting sheets were loaded in the printer. Then, the printer was leftto stand under an (N/N) environment at a temperature of 23° C. and arelative humidity of 50% for one day. Then, while the amount of thetoner supplied onto the developing roller in solid pattern printing wasfixed at 0.3 mg/cm², sheets were continuously printed at an imagedensity of 5%. Solid pattern printing (image density: 100%) was carriedout on the tenth sheet. Using a McBeth transmitting image densitometer,the image density, luminance (L*), color coordinate (a*, b*) and chroma(C*) of the tenth sheet were measured.

It is known that as the absolute value of a* or the hue angle increases,a secondary color (green) is produced and makes the yellow toner greenerin hue.

Table 1 shows the measurement and evaluation results of the yellowtoners of Examples 1 to 3 and Comparative Examples 1 to 3, along withthe toner composition.

In the following Table 1, “PY214” means C.I. Pigment Yellow 214; “SY162”means C.I. Solvent Yellow 162; “PY93” means C.I. Pigment Yellow 93; and“PY155” means C.I. Pigment Yellow 155.

TABLE 1 A Example 1 Example 2 Example 3 Colored resin particlesParticles (1) Particles (2) Particles (3) Compound A PY214 PY214 PY214Added amount (parts) 4.5 4.5 2.0 Compound B SY162 SY162 SY162 Addedamount (parts) 3.0 4.5 5.0 Other yellow colorant — — — Added amount(parts) — — — Compound A/B ratio 1.5 1.0 0.4 Dv (μm) 5.3 5.8 5.7 Dv/Dn1.19 1.17 1.22 Printing evaluation Amount of toner loaded on 0.3 0.3 0.3sheet (mg/cm²) Reflection density 1.31 1.36 1.27 Luminance L* 95.3 95.294.9 a* −11.7 −11.8 −11.0 b* 83.6 87.6 84.9 Chroma C* 84.4 88.4 85.6 Hueangle (°) 98.0 97.7 97.4 B Comparative Comparative Comparative Example 1Example 2 Example 3 Colored resin particles Particles (4) Particles (5)Particles (6) Compound A — — PY214 Added amount (parts) — — 8.0 CompoundB SY162 SY162 — Added amount (parts) 3.0 3.0 — Other yellow colorantPY93 PY155 — Added amount (parts) 4.5 4.5 — Compound A/B ratio — — — Dv(μm) 6.1 5.2 12.9 Dv/Dn 1.22 1.19 1.37 Printing evaluation Amount oftoner loaded on 0.3 0.3 0.3 sheet (mg/cm²) Reflection density 1.28 1.341.05 Luminance L* 93.8 94.9 95.4 a* −10.2 −9.2 −10.9 b* 83.3 88.2 69.7Chroma C* 83.9 88.7 70.5 Hue angle (°) 97.0 96.0 98.9

5. Evaluation of Toners

The yellow toner of Comparative Example 1 is a toner using the compoundB (C.I. Solvent Yellow 162) in combination with C.I. Pigment Yellow 93.For Comparative Example 1, the chroma C* is as low as 83.9; the absolutevalue of a* is as small as 10.2; and the hue angle is as small as 97.0°.Therefore, it is clear that the yellow toner is dull in color and lessgreen in hue when C.I. Pigment Yellow 93 is used in place of thecompound A and the toner on the sheet is 0.3 mg/cm² and smaller thanever before.

The yellow toner of Comparative Example 2 is a toner using the compoundB (C.I. Solvent Yellow 162) in combination with C.I. Pigment Yellow 155.Comparative Example 2 has no problem with sharpness since the chroma C*is 88.7. For Comparative Example 2, however, the absolute value of a* isas small as 9.2, and the hue angle is as small as 96.0°. These valuesare the smallest among the evaluated toners. Therefore, it is clear thatthe yellow toner is especially less green in hue when C.I. PigmentYellow 155 is used in place of the compound A and the toner on the sheetis 0.3 mg/cm² and smaller than ever before.

The yellow toner of Comparative Example 3 is a toner in which, withrespect to 100 parts by mass of the binder resin, 8.0 parts by mass ofthe compound A is only used as the yellow colorant. For ComparativeExample 3, the volume average particle diameter (Dv) is as large as 12.9μm, and the particle size distribution (Dv/Dn) is 1.37. Accordingly, theyellow toner of Comparative Example 3 is a toner with a wide particlesize distribution. From these results, it is clear that when the addedamount of the compound A is more than 7.5 parts, the particle diameterof the toner thus obtained increases overall, and the toner particlesare non-uniform in particle diameter.

For Comparative Example 3, since the hue angle is 98.9°, there is noproblem with green in hue. For Comparative Example 3, however, thechroma C* is as low as 70.5. This value is the smallest among theevaluated toners. Therefore, it is clear that the yellow toner isespecially dull in color when the compound A is used solely as theyellow colorant and the toner on the sheet is 0.3 mg/cm² and smallerthan ever before.

Meanwhile, the yellow toners of Examples 1 to 3 are toners in which,with respect to 100 parts by mass of the binder resin, 2.0 to 4.5 partsby mass of the compound A and 3.0 to 5.0 parts by mass of the compound Bare contained as the yellow colorant. For Examples 1 to 3, the volumeaverage particle diameter (Dv) is as small as 5.3 to 5.8 μm, and theparticle size distribution (Dv/Dn) as narrow as 1.17 to 1.22. Therefore,it is clear that the toners of Examples 1 to 3 have the desired particlediameter and are narrow in particle size distribution.

Also for Examples 1 to 3, the chroma C* is as high as 84.4 or more; theabsolute value of a* is as large as 11.0 or more; and the hue angle isas large as 97.4° or more. Therefore, it is clear that even when thetoner on the sheet is 0.3 mg/cm² and smaller than ever before, theyellow toners of Examples 1 to 3 in which, with respect to 100 parts bymass of the binder resin, 0.5 to 7.5 parts by mass of the compound A and0.5 to 8.0 parts by mass of the compound B are contained as the yellowcolorant, are each a toner that it provides a sharper color than everbefore and the hue is greener than ever before.

1. A yellow toner comprising a binder resin and a yellow colorant,wherein, as the yellow colorant, a compound A represented by thefollowing general formula (1) and a compound B represented by thefollowing formula (2) are contained, and wherein, with respect to 100parts by mass of the binder resin, a content of the compound A is from0.5 to 7.5 parts by mass, and a content of the compound B is from 0.5 to8.0 parts by mass:

where R^(1A), R^(1B), R^(2A) and R^(2B) are each independently a halogenatom, an alkyl group, a methoxy group, an amino group, a nitro group, anacetylamido group (—NHCOCH₃), a methyl ester group (—COOCH₃) or aprimary amide group (—CONH); R³ is a halogen atom; R⁴ and R⁵ are eachindependently a halogen atom, an alkyl group, a methoxy group, an aminogroup, a nitro group, an acetylamido group (—NHCOCH₃), an acetyl group(—COCH₃), a methyl ester group (—COOCH₃) or a primary amide group(—CONH₂); a1 and b1 are positive integers that a sum of the positiveintegers is 1 or more and 3 or less; a2 and b2 are positive integersthat a sum of the positive integers is 1 or more and 3 or less; c is aninteger of 1 or more and 3 or less; and d and e are each independently 1or 2,


2. The yellow toner according to claim 1, wherein a mass ratio of thecontent of the compound A to the content of the compound B (compoundA/compound B) is from 0.1 to 10.0.